package com.atguigu.springcloud.lb;

import org.springframework.cloud.client.ServiceInstance;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * Ribbon 手写轮询算法
 *
 * @author ThinkPad
 */
public class MyLB implements LoadBalancer {

    private AtomicInteger atomicInteger = new AtomicInteger(0);

    public final int getAndInctrement() {
        int current;
        int next;
        do {
            current = this.atomicInteger.get();
            next = current >= 2147483647 ? 0 : current + 1;
        } while (!this.atomicInteger.compareAndSet(current, next));
        System.out.println("*****第几次访问，次数next：" + next);
        return next;
    }

    @Override
    public ServiceInstance instances(List<ServiceInstance> serviceInstanceList) {
        int index = getAndInctrement() % serviceInstanceList.size();

        return serviceInstanceList.get(index);
    }
}
